What percent, by mass, is Oxygen in the compound Fe (OH) 3?

Mass percent of oxygen in Fe (OH) 3 = 44.92%

Explanation:Percentage by mass is a way of representing the concentration of an element in a compound. It is calculated as the mass of the element divided by the total mass of the compound, multiplied by 100.

•First find the total mass of the compound

•Molar mass of Fe = 55.85g/mol

•Molar mass of O = 16g/mol

•Molar mass of H=1g/mol

From these we can calculate the molecular mass of Fe (OH) 3 = 55.85g/mol + (16g/mol) 3 + (1g/mol) 3

=55.85g/mol + 48g/mol + 3g/mol

=106.85g/mol

Mass percent of a element = mass of element/total mass of compound * 100

Since we have 3 atoms of oxygen in the compound, the mass of oxygen present is 48g/mol

Mass percent of oxygen = 48g/mol/106.85g/mol * 100

= 0.4492*100 = 44.92%

Therefore the mass percent of oxygen in the compound Fe (OH) 3 is 44.92%